The oil-immersed test transformer is a new type of high-voltage test equipment. This series of products adopts a single-frame core iron core structure. The primary winding and the high-voltage winding are coaxially wound on the iron core, thereby reducing the leakage flux and increasing the inter-winding coupling. The product has a compact overall structure, strong versatility, and easy to use and carry. It is suitable for power systems and power users to test the insulation performance of various high-voltage electrical equipment on-site. It is a necessary test instrument for power equipment detection and preventive testing.

You introduce the operation precautions for the power frequency withstand voltage test of the oil-immersed test transformer:

1. The test personnel should do a good job in the division of labor and clarify the method of mutual connection. And there is a dedicated person to supervise on-site safety and observe the status of the test product.

2. The tested product should be cleaned and dried first to avoid damage to the tested product and errors caused by the test.

3. For large-scale tests, airlift tests should generally be carried out first. That is, when the test product is not connected, the voltage is increased to the test voltage, various meters are proofread, and the ball gap is adjusted.

4. The boost speed cannot be too fast, and sudden pressure must be prevented. For example, the sudden closing of the voltage regulator is not in the zero position. The power can not be cut off suddenly, and the switch should generally be opened when the voltage regulator drops to zero.

5. When the voltage rises to the test voltage, start timing. After 1 minute, quickly drop the voltage to below 1∕3 test voltage before turning on the power supply.

6. During the boost or withstand voltage test, if the following abnormal conditions are found, the voltage should be reduced immediately and the power supply should be cut off. Stop the test and find out the reason:

1) The pointer of the voltmeter swings greatly; 2) The insulation is found to be burnt or smoking; 3) There is an abnormal sound in the test product.

7. The insulation resistance should be measured before and after the withstand voltage test, and the insulation condition should be checked.

8. The test transformer is connected during the DC withstand voltage or leakage test of the tested product.